Today, Transparency International launches the 2019 Corruption Perception Index (CPI), our flagship piece of global research. Ironically, whilst it’s probably why most people have heard of us, there’s an awful lot of confusion still about what the CPI does and does not do. So to help you navigate this year’s results, I’ve written a short overview of what the CPI is and what it means for the UK.

It’s a survey of surveys

The CPI is a survey of surveys, or in fancier parlance a composite index. Countries’ headline scores are based on up to thirteen underlying surveys (the UK is based on eight this year), which are standardised and made comparable between jurisdictions and over time. Although it’s the headline score most people focus on, remember there is more detail underneath that is worth digging into. All of this data is made available on our Secretariat’s website here.

It measures perceptions of public sector corruption only

The CPI measures expert perceptions of corruption. The trick is in the name. Let’s break this down, though, because it’s one of the bits a lot of the CPI’s users get wrong.

Firstly, the underlying surveys which form the CPI are usually based on responses from academics, country specialists and business executives. This is not a survey of our colleagues or a survey of citizens, it is a review of expert opinion.

Secondly, it focuses on perceptions of corruption. Again, this nuance is sometimes lost. Whilst the survey does provide authoritative judgement on the seriousness of corruption within a particular jurisdiction, it does not seek to measure the actual level. So probably best to avoid stating something like ‘country x is the most corrupt in the world’. This could well be true, but it is not what the CPI actually says.

And finally, it measures public sector corruption only. At TI, we define corruption as ‘the abuse of entrusted power for private gain’. Many of the surveys forming the CPI ask respondents about the prevalence of bribery and embezzlement in the government, legislature and the judiciary. It does not provide comment on how a country facilitates corruption elsewhere in the world; however, we have produced a whole series of reports on this, for example here, here, here, here and here.

Some important bits of detail to note

Although the CPI goes back 25 years to 1995, due to a change in its methodology you can only really compare headline scores from 2012. Also in the small print, there are some techie bits of maths that are worth paying attention to. Now this may get a bit too much into the detail for your liking, but nonetheless it’s very important.

Because the CPI is a survey of surveys and one based on a range of experts, unsurprisingly, the underlying reviews that form it have slightly different results. For example, the World Economic Forum’s global competitiveness report gives the UK a 58, whilst the IMD World Competitiveness Yearbook gives it 79. Both of these surveys ask respondents about perceived levels of bribery and embezzlement. In mathematical terms this is called ‘variance’.

To reflect this range of views, the headline CPI scores (for example, the UK’s 77 this year) should be read with this in mind. When you take into account this variance (see the standard error in the results) you can tell whether the change in a country’s score is statistically significant. What does this mean? It means if a country drops, say, three points, but the standard error is bigger than three, we cannot really claim the drop is significant because it might be due to some wild variation in the underlying survey. In circumstances like this, you should pay close attention to why there’s such a divergence of views to fully understand what the data is telling you.

What to take away from the UK’s latest score

Taking into account the above, we think the following is a reasonable assessment of the UK’s latest score and how it should respond. Like many other advanced industrial economies, perceptions of corruption in our public sector are certainly not improving. These results are a stark reminder that there is no room for complacency in the fight against global corruption. While the UK made some significant strides to tackle dirty money in recent years, it is concerning to see its score relating to perceived public sector corruption stagnating. The new Government now has an opportunity to pull the UK back into the top 10. To do so it will need considerable ambition that will put anti-corruption front and centre of public policy both at home and abroad.